[docs] [issue28951] re.flags not documented in Module Contents as promised.

Change by Serhiy Storchaka <storchaka+cpython@gmail.com>: ---------- components: +Regular Expressions nosy: +ezio.melotti, mrabarnett stage: -> needs patch versions: +Python 2.7, Python 3.6, Python 3.7 -Python 3.5 _______________________________________ Python tracker <report@bugs.python.org> <https://bugs.python.org/issue28951> _______________________________________